flow-static-land - npm Package Compare versions

Comparing version 0.2.2 to 0.2.3

CHANGELOG.md

@@ -15,2 +15,9 @@ # Changelog
 
+## 0.2.3
+
+- **New Feature**
+  - `Foldable`: add default `foldMap` implementation (@gcanti)
+  - `ChainRec` (@gcanti)
+  - `Yoneda` (@gcanti)
+
 ## 0.2.2
@@ -17,0 +24,0 @@

package.json

 {
   "name": "flow-static-land",
-  "version": "0.2.2",
+  "version": "0.2.3",
   "description": "Implementation of common algebraic types in JavaScript + Flow",
@@ -5,0 +5,0 @@ "files": [

README.md

@@ -9,2 +9,22 @@ # Features
 
+- `Semigroup`
+- `Monoid`
+- `Functor`
+- `Applicative`
+- `Monad`
+- `Foldable`
+- `Traversable`
+- `ChainRec`
+- `Alternative`
+- `Eff`
+- `Arr`
+- `Maybe`
+- `Either`
+- `Task`
+- `State`
+- `Writer`
+- `Reader`
+
+and many more...
+
 # Example
@@ -52,3 +72,2 @@
 - [Phantom types with Flow](https://medium.com/@gcanti/phantom-types-with-flow-828aff73232b)
-- [Refinements with Flow](https://medium.com/@gcanti/refinements-with-flow-9c7eeae8478b)
 
@@ -55,0 +74,0 @@ # More examples

src/Arr.js

@@ -67,4 +67,4 @@ // @flow
 
-export function reduce<A, B>(f: (a: A, b: B) => A, a: A, fb: Arr<B>): A {
-  return prj(fb).reduce(f, a)
+export function reduce<A, B>(f: (b: B, a: A) => B, b: B, fa: Arr<A>): B {
+  return prj(fa).reduce(f, b)
 }
@@ -71,0 +71,0 @@

src/Compose.js

@@ -58,4 +58,4 @@ // @flow
 
-  function reduce<A, B>(f: (a: A, b: B) => A, a: A, fb: HKT<IsCompose<F1, F2>, B>): A {
-    return f1.reduce((a, gb) => f2.reduce(f, a, gb), a, prj(fb))
+  function reduce<A, B>(f: (b: B, a: A) => B, b: B, fa: HKT<IsCompose<F1, F2>, A>): B {
+    return f1.reduce((a, gb) => f2.reduce(f, a, gb), b, prj(fa))
   }
@@ -62,0 +62,0 @@

src/Either.js

@@ -113,8 +113,8 @@ // @flow
 
-export function reduce<L, A, B>(f: (a: A, b: B) => A, a: A, fb: Either<L, B>): A {
-  const b = prj(fb)
-  if (b instanceof Left) {
-    return a
+export function reduce<L, A, B>(f: (b: B, a: A) => B, b: B, fa: Either<L, A>): B {
+  const a = prj(fa)
+  if (a instanceof Left) {
+    return b
   }
-  return f(a, b.value0)
+  return f(b, a.value0)
 }
@@ -121,0 +121,0 @@

src/Foldable.js

 // @flow
+import type { Monoid } from './Monoid'
+
 import { HKT } from './HKT'
 
+/*
+
+  `Foldable` represents data structures which can be _folded_.
+
+  - `foldr` folds a structure from the right (not implemented)
+  - `foldl` folds a structure from the left
+  - `foldMap` folds a structure by accumulating values in a `Monoid`
+
+  reduce = foldl
+
+*/
+
 export interface Foldable<F> {
-  reduce<A, B>(f: (a: A, b: B) => A, a: A, fb: HKT<F, B>): A
+  reduce<A, B>(f: (b: B, a: A) => B, b: B, fa: HKT<F, A>): B
 }
+
+/* A default implementation of `foldMap` using `foldl`. */
+export function foldMap<F, M, A>(foldable: Foldable<F>, monoid: Monoid<M>, f: (a: A) => M, fa: HKT<F, A>): M {
+  return foldable.reduce((acc, x) => monoid.concat(f(x), acc), monoid.empty(), fa)
+}

src/Identity.js

@@ -14,3 +14,8 @@ // @flow
 import type { Comonad } from './Comonad'
+import type { ChainRec } from './ChainRec'
+import type { Either } from './Either'
 
+import { tailRec } from './ChainRec'
+import { compose } from './Fun'
+
 class IsIdentity {}
@@ -46,4 +51,4 @@
 
-export function reduce<A, B>(f: (a: A, b: B) => A, a: A, fb: Identity<B>): A {
-  return f(a, prj(fb))
+export function reduce<A, B>(f: (b: B, a: A) => B, b: B, fa: Identity<A>): B {
+  return f(b, prj(fa))
 }
@@ -65,2 +70,6 @@
 
+export function chainRec<A, B>(f: (a: A) => Identity<Either<A, B>>, a: A): B {
+  return tailRec(compose(extract, f), a)
+}
+
 export function getSetoid<A>(setoid: Setoid<A>): Setoid<Identity<A>> {
@@ -110,3 +119,4 @@ return {
     extend,
-    extract
+    extract,
+    chainRec
   }: Monad<IsIdentity> &
@@ -117,3 +127,4 @@ Foldable<IsIdentity> &
      Extend<IsIdentity> &
-     Comonad<IsIdentity>)
+     Comonad<IsIdentity> &
+     ChainRec<IsIdentity>)
 }

src/Maybe.js

@@ -91,5 +91,5 @@ // @flow
 
-export function reduce<A, B>(f: (a: A, b: B) => A, a: A, fb: Maybe<B>): A {
-  const b = prj(fb)
-  return b == null ? a : f(a, b)
+export function reduce<A, B>(f: (b: B, a: A) => B, b: B, fa: Maybe<A>): B {
+  const a = prj(fa)
+  return a == null ? b : f(b, a)
 }
@@ -96,0 +96,0 @@

No alert changes

Improved metrics

Total package byte prevSize

193650

increased by1.65%

Number of package files

153

increased by1.32%

Lines of code

4171

increased by1.98%

Number of lines in readme file

102

increased by22.89%

No dependency changes